(1) extra-embryonic blood vessels ---blood island: at the middle of 3 rd week, wall of the yolk sac mesenchyma proliferate and form isolated cell clusters, the peripheral cell become flattened and differentiate into endothelial cell to from endothelial tube; central located cells are detached and develop into primitive blood cells(blood stem cell)

digestive and respiratory system derived from primitive gut /foregut /midgut /hindgut ---epi. of digestive and respiratory system derived from endoderm ---CT and MT of digestive and respiratory system derived from splanchnic or visceral mesoderm

---a science which study the processes and regulations of development of human fetus.(from 1 cell(zygote) to (5-7)X1012 cells ) ---total 38 weeks: preembryonic period: before 2 weeks

1. Development of branchial apparatus * branchial apparatus: including branchial arch, branchial groove, branchial membrane and branchial pouch

1. Components ---ovary: produce ovum secrete female sex hormones ---oviduct: duct for fertilized ovum(zygote) passing through place where fertilization takes place ---uterus: organ where the fetus grow up ---vagina

1. Components: ---testis: produce the male germ cells- gametes(sperm) produce androgen-testosterone ---gernital ducts: store and conduct the sperm epididymis ductus deferens ejaculatory duct

1. Components ---kidney : produce urine ---ureters ---bladder -cavity organs, conduct, store and ---urethra remove the urine ---functions: remove waste products of metabolism regulate the homeostasis secrete some bioactive factors- renin, erythropoietin

1. Components ---nose ---pharynx ---larynx ---trachea ---bronchi ---lung

---small gland: fundis gland, small intestinal gland ---large gland: salivary gland, pancreas, liver

---Digestive system: Digestive tract Digestive gland